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Dumb Spare Tire Question

2nd 392

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Burnt up clutches in 392s prove its an interior design and is not a function of different tire sizes. One of the reasons I'd never buy a Jeep that doesn't offer 2HI is durability. Clutches are a potential failure point that I don't want and I definitely don't need the Jeep to decide when I need 4HI. Give me a standard 231/241 and I'll pull the lever when I need it.
Unfortunately if you want a V8 it’s take it with virtually every available option including the TC and 4 dr, with the XR even standard for 24. Sux, but I took it.
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stumblinhorse

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Burnt up clutches in 392s prove its an interior design and is not a function of different tire sizes. One of the reasons I'd never buy a Jeep that doesn't offer 2HI is durability. Clutches are a potential failure point that I don't want and I definitely don't need the Jeep to decide when I need 4HI. Give me a standard 231/241 and I'll pull the lever when I need it.
I didn’t say burned up clutches in a 392 was due to different tire sizes. You said that. What I said is that the mp3022 cannot handle different tire sizes. Where we started was different tire sizes don’t matter. That isn’t true to all wranglers. You stated that rear wheel slip causes front drive engagement, that isn’t true in all cases. The mp3022 will slip clutches simply sitting still and turning the steering wheel. There are different models in different wranglers. I wish the 392 had rock trac. It doesn’t. Not going to ever change from the factory. So just trying to make sure people know that what everyone says is not always correct. Anymore “it depends” is the best answer. And know what options and model you own so you can make good decisions.
 

Shibadog

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Okay I understand now, I think. To drive in 4 wheel drive Hi and Lo gear the tires need to be the same diameter. (Wondering if I should start paying more attention to getting the tires even when airing down...)

I drive on road in rear-wheel drive. I wasn't aware some Jeeps didn't have a rear-wheel drive option. But this is great information, it sounds like if I need to use that spare on the trail I would want to limp it in rear-wheel drive off the trail.
like them all the same size. If you’re off road you may not be ABLE to limp in with rear wheel drive only. If you regularly go places where 4wd is needed, I’d spring for another tire.
 

Steph1

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Just buy a 5th one and stop worrying, as I know it would make ME feel better. Be sure you throw the spare in the tire rotation and the extra expense will pay for itself, since each tire will get a break at every 5th rotation.
 

Zandcwhite

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I didn’t say burned up clutches in a 392 was due to different tire sizes. You said that. What I said is that the mp3022 cannot handle different tire sizes. Where we started was different tire sizes don’t matter. That isn’t true to all wranglers. You stated that rear wheel slip causes front drive engagement, that isn’t true in all cases. The mp3022 will slip clutches simply sitting still and turning the steering wheel. There are different models in different wranglers. I wish the 392 had rock trac. It doesn’t. Not going to ever change from the factory. So just trying to make sure people know that what everyone says is not always correct. Anymore “it depends” is the best answer. And know what options and model you own so you can make good decisions.
You're still ignoring the fact that many grand Cherokees then come with a spare they can't use by your interpretation?
 

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stumblinhorse

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You're still ignoring the fact that many grand Cherokees then come with a spare they can't use by your interpretation?
The owners manual tells you you cannot drive more than 50 miles on a donut spare. I guess if you’re trying to say that I said it cannot be done, that is not what I am saying. I am saying that it is not designed to have different tire sizes installed. I am saying you will burn out the clutches in doing so.
 

Zandcwhite

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The owners manual tells you you cannot drive more than 50 miles on a donut spare. I guess if you’re trying to say that I said it cannot be done, that is not what I am saying. I am saying that it is not designed to have different tire sizes installed. I am saying you will burn out the clutches in doing so.
The op was talking mismatched but same size spare, far less of a difference than the donut spare vs full size tire that works in the grand. If I got a flat in the ops scenario in moab would I drive 1100 miles home? No but I wouldn't do that with a matched spare either. Even if he has the full time tcase he'd be fine running the slightly different tire until he could replace it was my point all along. The 50 mile recommendation for donut spares has nothing to do with clutches or side gears or any of the other reasons people want to tie to that limitation. It's a garbage tire made of a suit compound that is only good for temporary use.
 

stumblinhorse

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The op was talking mismatched but same size spare, far less of a difference than the donut spare vs full size tire that works in the grand. If I got a flat in the ops scenario in moab would I drive 1100 miles home? No but I wouldn't do that with a matched spare either. Even if he has the full time tcase he'd be fine running the slightly different tire until he could replace it was my point all along. The 50 mile recommendation for donut spares has nothing to do with clutches or side gears or any of the other reasons people want to tie to that limitation. It's a garbage tire made of a suit compound that is only good for temporary use.
If you say so. I am only in this thread to say that for some wrangler t-cases, a few hundred miles on a different size spare will do damage. If you are saying that is not the case then that is up to you and the folks that choose to follow your advice.
 

Camaroboi13

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2017 WK2 limited v6 owner. Mine came with a full height spare that was super skinny, like a donut. Same diameter as stock tires though. The owners manual says 50 miles only because it’s a much thinner tire with much thinner tread. Has nothing to do with burning clutches anywhere.
 
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jerrygcoffey

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I'm planning on measuring the actual diameter of the tires once they're received to ensure they are virtually the same. Worst case scenario I ensure the mismatched spare is on the front if I need to drive on the highway. I will plan on ordering a fifth tire for Christmas.
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